new index atom name original index 1 C 13 2 C 12 3 C 10 4 C 11 5 C 8 6 C 9 7 C 7 8 O 6 9 O 4 10 O 5 11 O 2 12 O 3 13 O 1 14 H 27 15 H 26 16 H 25 17 H 19 18 H 17 19 H 18 20 H 15 21 H 16 22 H 14 23 H 24 24 H 22 25 H 23 26 H 20 27 H 21